BirdAnalyst
Species · BCR 27 · BBS 2025 Release · 1966–2024

Boat-tailed Grackle In Southeastern Coastal Plain

All regionsSoutheastern Coastal PlainGeneralists

Boat-tailed Grackle in Southeastern Coastal Plain has declined: down 35% on the route-weighted index since 1968.

-35%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
85Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Boat-tailed Grackle in Southeastern Coastal Plain. See the full index history below.

Forecast

If the recent trend holds, Boat-tailed Grackle in Southeastern Coastal Plain is projected to rise about 138% by 2029 — from 0.36 in 2024 to a central estimate of 0.86 (95% range 0.22–1.5). A 5-year backtest shows a typical error of ±98.4%, with 80% of held-out values landing inside the 95% band.

+138%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.86Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.22–1.595% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±98.4%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Boat-tailed Grackle in Southeastern Coastal Plain is projected to rise about 138% by 2029 — from 0.36 in 2024 to a central estimate of 0.86 (95% range 0.22–1.5). A 5-year backtest shows a typical error of ±98.4%, with 80% of held-out values landing inside the 95% band.19662029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.850.221.5
20260.850.221.5
20270.850.221.5
20280.860.221.5
20290.860.221.5

Routes In Southeastern Coastal Plain

Routes recording Boat-tailed Grackle in Southeastern Coastal Plain.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
DarienGEORGIA752019
Colonels IslandGEORGIA442023
Johns IsleSOUTH-CAROLINA411979
JarvisburgNORTH-CAROLINA361999
NewtonGEORGIA212016
ShallotteNORTH-CAROLINA171991
BelmontFLORIDA132024
MerrimonNORTH-CAROLINA122023
Chacaloochee BayALABAMA112019
Myrtle GroveNORTH-CAROLINA112024
Cross CityFLORIDA102023
Kiawah IslandSOUTH-CAROLINA102024
Bay MinetteALABAMA92015
Dauphin Is 3ALABAMA82021
CallahanFLORIDA82004
Dauphin IsALABAMA71990
Hixtown SwmpFLORIDA72005
St Vincent IFLORIDA72024
NecaiseMISSISSIPPI62022
FoleyALABAMA51972
Milltail CrNORTH-CAROLINA52024
Jarvisburg 2NORTH-CAROLINA52021
Alabama PtALABAMA42003
Dauphin Is 2ALABAMA42019
OwensboroGEORGIA42024

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.